The Newmarket-based Animal Health Trust (AHT)has been investigating Seasonal Canine Illness (SCI) reported at a number of locations around the UK, including Thetford Forest and Rendlesham Forest in Suffolk.

Dr Richard Newton, of the AHT, who is leading the SCI investigation, said: “We are hopefully coming towards the end of the second autumn in which we have been investigating SCI, with fewer cases being reported to us in the past few weeks.

“We have managed to collect a lot of information from vets and also from dog owners since we became aware of the recurrence of SCI at the beginning of September.”

In September scientists from the AHT visited specific, SCI-affected areas on the Sandringham Estate, one of its SCI investigation sites, with British field botanist, Dr Mark Spencer, from the Natural History Museum.

Dr Spencer stated there was no obvious evidence of any plants, fungi, blue-green algae or bracken spore toxins, which had been proposed as causes, which would cause the clinical signs of SCI in dogs through direct contact.

Dr Newton said: “Mark was confident that there was nothing obviously unusual in the woodlands and that the plants and habitats he observed did not provide evidence of abundant and recently emerged botanical or fungal species that would explain the recent autumnal re-emergence of SCI at the Sandringham Estate”.

“Because of this we have been looking at other possible causes.

“Information made available to us in 2011 suggests there may be links between SCI and harvest mites, and to a lesser extent links between SCI and wood pigeons, and perhaps other bird species. “We have been working with experts in the necessary fields, in the UK and internationally, to follow up these lines of enquiry.”

The AHT is continuing its investigation based at five sites – Sandringham Estate and Thetford Forest in Norfolk, Clumber Park and Sherwood Forest in Nottinghamshire, and Rendlesham Forest in Suffolk.

It is still requesting that owners who have walked their dogs at any of the five study sites since the beginning of August 2011 complete the relevant questionnaire on the AHT website, regardless of whethertheir dogs became ill.

Getting information from non-affected animals is just as important to the investigation as that provided for sick dogs, experts say. The charity expects that the number of cases will start to rapidly decline in the next few weeks, as they did at this time in 2010.